Methods and systems are provided for regenerating and purging a particulate filter of an exhaust treatment system for a combustion engine. In one example, a method may include flowing exhaust gas in a reverse direction through the particulate filter to purge particulate matter to an intake manifold of the engine for combusting. The duration of purging may be based on a regeneration achieved during a previous regeneration of the particulate filter during a deceleration fuel shut-off event.

An exhaust after-treatment system includes a first set of exhaust after-treatment components, a second set of exhaust after-treatment components, an inlet to the exhaust after-treatment system, an outlet from the exhaust after-treatment system, and a valve and conduit arrangement configurable in a plurality of modes, in a first mode, exhaust gas entering the inlet flows through the second set of exhaust after-treatment components, then through the first set of exhaust after-treatment components, and then through the outlet. In a second mode, exhaust gas entering the inlet flows through the second set of exhaust after-treatment components without flowing through the first set of exhaust after-treatment components, and then through the outlet in a third mode, exhaust gas entering the inlet flows through the first set of exhaust after-treatment components, then through the second set of exhaust after-treatment components, and then through the outlet.

A heater system for an exhaust system is provided. The heater system includes a heater disposed in an exhaust conduit. The heater includes a plurality of heating elements disposed in the exhaust conduit. A heating control module controls the plurality of heating elements differently according to operating conditions specific to each heating element. In other forms, the heater system for an exhaust system has a plurality of heating zones, instead of a plurality of heating elements. The heating control module controls the plurality of heating zones differently according to operating conditions specific to each heating zone.

A method of predicting temperature of at least one location in a fluid flow system that has a heating system for heating fluid. The method includes obtaining a mass flow rate of fluid flow of the fluid flow system, obtaining at least one of a fluid outlet temperature and a fluid inlet temperature of a heater of the heating system, obtaining power provided to the heater, and calculating temperature at the at least one location based on a model of the fluid flow system and the obtained mass flow rate, fluid outlet temperature, and fluid inlet temperature.

An exhaust system includes a first exhaust after-treatment system receiving exhaust gases generated by an engine, a second exhaust after-treatment system downstream of the first exhaust after-treatment system, and at least one bypass connecting an engine outlet to an inlet to the second exhaust after-treatment system. A turbocharger is associated with the bypass and a bypass valve is located upstream of the turbocharger. The bypass valve is moveable between an open position to bypass exhaust gas flow to the first exhaust after-treatment system, a closed position to direct all exhaust gas flow to the first exhaust after-treatment system, and a partially open position where one portion of exhaust gas flow is directed into the first exhaust after-treatment system and a remaining portion of exhaust gas flow is directed into the turbocharger. A controller controls movement of the bypass valve between the open, closed, and partially open positions.

Methods and systems are provided for filtering particulate matter in an exhaust passage of an engine system. In one example, a method may include during a cold start condition comprising an engine temperature being less than a threshold engine temperature, directing engine exhaust gas to an exhaust particulate filter, and during a warm engine condition, directing engine exhaust gas to bypass the exhaust particulate filter, wherein the warm engine condition comprises the engine temperature being greater than or equal to the threshold engine temperature and fuel being combusted in the engine. In this way, the exhaust particulate filter may be reliably regenerated during engine shutdown events such as DFSOs while reducing filter degradation, and lowering PM emissions.

A method of removing impurities from a gas including the steps of removing impurities from biogas comprising at least one adsorbents via a process vessel or reactor, directing the purified gas to an device to generate power and/or heat, regenerating the saturated adsorption media with the waste heat recovered from the engine exhaust and directing the regeneration gas (hot air or engine exhaust) to flare, engine exhaust stack, or atmosphere.

Embodiments described herein methods can be used in particulate filter regeneration, such as particulate filters used for filtering the exhaust of an engine, e.g., a diesel engine. Systems herein can be configured to dispense combustion gas(es) into housing were a particulate filter is contained and to ignite the combustion gases. Methods for conducting a safety verification process of such systems are disclosed, as well as methods for regenerating the filters. Still other embodiments are described.

A control system for a heating system of an exhaust system is provided. The control system includes at least one electric heater disposed within an exhaust fluid flow pathway, and a control device adapted to receive at least one input selected from the group consisting of mass flow rate of an exhaust fluid flow, mass velocity of an exhaust fluid flow, flow temperature upstream of the at least one electric heater, flow temperature downstream of the at least one electric heater, power input to the at least one electric heater, parameters derived from physical characteristics of the heating system, and combinations thereof. The control device is operable to modulate power to the at least one electric heater based on at least one input.

A system includes a catalyst for receiving and treating exhaust gas generated by an engine, a passive NOx adsorber (PNA) positioned upstream of the catalyst, a bypass valve positioned upstream of the catalyst and the PNA, and a controller. The controller is configured to, determine that the catalyst is operating under cold start conditions, control the bypass valve to direct exhaust gas to the PNA, determine that the catalyst is no longer operating under cold start conditions and continue to control the bypass valve to direct exhaust gas to the PNA for a predetermined duration, and after the elapse of the predetermined duration, control the bypass valve to direct exhaust gas to the catalyst bypassing the PNA. The controller is also configured to detect a high transient torque demand while the exhaust gas is provided to the PNA, and split the torque demand between the engine and an electric motor.